DOC declares war on Antipodes mice

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DOC is about to begin a million-dollar ground war on an army of mice on the Antipodes Islands.

They hope mice will soon be the endangered species on the island instead of the native birds and insects that call the remote subantarctic islands home.

At the end of this month the mission to eradicate mice - thought to have been introduced early last century by shipwreck - will be launched.

DOC Antipodes Islands mouse eradication project manager Stephen Horn said, with a million dollars raised towards the project, and a series of trials already completed, it was time to start what would be a long battle.

The Antipodes were home to a wide range of rare wildlife, birds and plants, Horn said.

They are the breeding home of the antipodean wandering albatross, and a variety of petrel along with the Antipodes Island snipe and pipit, two parakeets and at least nine endemic insect species.

The mice threatened the insects and plants, along with bird eggs and young chicks, he said.

As part of the expedition, scientists will assess the populations of non-target species including the Antipodes parakeet, the Reischek's parakeet, the Antipodes Island snipe and the Antipodes Island pipit on Bollons Island.

"The species on Bollons will act as a genetic reservoir," Horn said.

Non-toxic bait trials conducted last year showed the parakeets and snipe did not uptake the bait while a small percentage of pipits did.

"We believe non-target species won't be at risk, but by ensuring a reservoir on Bollons Island, we can be prepared," Horn said.

Scientists would capture a population of the pipits and conduct husbandry trials and captive management, he said.

They would also gather baseline data to chart ecosystem recovery once mice were gone.

A hut on the island will also be repaired to give staff involved in the project somewhere to live during the harsh winters ahead.

"A landslip at the start of the year has destroyed the hut, which means conditions will be a bit dire for staff until we can get some repairs done," Horn said.

While plenty of work has been done behind the scenes for the Million Dollar Mouse project, the next phases will be public.

Tenders for helicopter and shipping options are being looked at to transport the bait, staff and equipment needed to wipe out the mice during coming winters.

Baiting can only be done in winter because the mice are at their most vulnerable, and non-target species and other birds that breed on the Antipodes Islands are at their lowest numbers during winter.

Horn credited economist and environmental campaigner Gareth Morgan for getting the eradication project going after visiting the islands several years ago.

Ridding the Antipodes Islands of mice was one of DOC's long-term goals but the support Morgan and his group had offered as part of the Million Dollar Mouse campaign would make it a reality much sooner, Horn said.

However, Horn said the islands, 800km southeast of Bluff, were "ecological treasures" and the work to eradicate mice was vital.

"They are . . . critical breeding habitats for Antipodean albatross, white-capped mollymawk, white-chinned petrel, grey petrel, soft-plumaged petrel and black-bellied storm petrel. As well, there are at least 20 insect species and at least three plants that are restricted to these islands," he said.

The islands serviced millions of square kilometres of ocean. Seabirds travelled thousands of kilometres but needed a place to breed.

"If we succeed, we have made an ecological investment for perpetuity," Horn said.

Funds will continue to be raised by a partnership that includes the Morgan Foundation, DOC, the World Wildlife Fund, the Fiordland Conservation Trust, Heritage Expeditions, and Kiwibank.

THE ANTIPODES

The volcanic Antipodes Island group lies 860 kilometres to the southeast of New Zealand's Stewart Island/Rakiura. The group consists of the main Antipodes Island (around 2000 hectares), Bollons Island to the north (20ha), and several other smaller islets and rocks.

THE TRIALS

Non-toxic bait trials were conducted on the Antipodes Island, with bait laid in a designated grid. The bait was laced with a biotracer that showed up under UV light. Mice in the grid were captured and results showed they were attracted to the bait. Non-target species consisting of parakeets and snipe did not take the bait, while a small percentage of pipits did.